220 



SCIENCE. 



[N. S. Vol. XI. No. 267. 



teen hundred feet in thickness, and ap- 

 parently contain a very large proportion 

 of volcanic materials. They seem to rest 

 unconformably on a thick series of plant 

 bearing, fresh water beds, which have been 

 considered Eocene. The Columbian lavas 

 rest apparently unconformably upon the 

 John Day beds. 



On the basis of lithologic and strati- 

 graphic characters, the John Day System 

 may be divided into three divisions, lower, 

 middle, and upper John Day. The lower 

 beds are mainly colored a brilliant red, 

 seem to have suffered more disturbance 

 than the higher beds and are practically 

 barren of fossils. The middle beds are blue, 

 green or drab, and are in in places quite 

 fossiliferous. The upper beds are bluff or 

 white. They are largely made up of vol- 

 canic material. Many fossils have been 

 obtained from this division. One horizon 

 particularly is rich in rodent remains. 



The writer's study of the vertical range of 

 the John Day species has not progressed far 

 enough to permit of any definite statement 

 regarding their zonal arrangement. Profes- 

 sor J. L. Wortman has already proposed 

 the division of the system, on faiinal 

 grounds, into upper Meryeochaerus and lower 

 Dieeratherinm beds. The use of the lith- 

 ologic divisions here proposed will greatly 

 aid in the study of the vertical range or 

 history of John Day species. 



Notes concerning erosion forms and exposures in 

 the deserts of South Central Utah. By J. E. 

 Talmage, Salt Lake City, Utah. 

 A description of the effects of denudation 

 in the region lying east and south of the 

 Thousand Lake Mountain, and west of the 

 water pocket fold. The dissection of the 

 Trias and Jura was illustrated by numerous 

 photographs. In the work of rock disinte- 

 gration much importance was attached to 

 the great diurnal range of temperature, the 

 range being 80° to 85° F. during the autumn 



months. Dykes and hills are prominently 

 exposed in certain parts of the region. 

 Selenite geodes similar to that first reported 

 in Science, February 17, 1893, are of fre- 

 quent occurrence. 



On certain peculiar markings on sandstones 



from the vicinity of Elen Canon, Arizona. 



By J. E. Talmage, Salt Lake City, Utah. 



The paper was illustrated by photographs 

 and slabs of the rock. The markings ap- 

 pear as right lines with approximately rec- 

 tangular intersections ; the lines are shallow 

 troughs from .5 mm. to 2 mm. in width 

 though occasionally in coarser rocks they 

 are as much as 9 mm. wide and 3 mm. 

 deep. The rectangles have an average size 

 of about 4x6 mm. Unbroken lines of 395 

 cm. have been traced. The rock is a fine- 

 formed argillaceous sandstone of brick red 

 to chocolate color. It occurs as a bed two 

 feet thick between coarser sandstones. 

 Ripple marks, rain drop impressions and 

 sun cracks appear in the marked rock. 



Attempts to reproduce the right line 

 markings were described, leading to the 

 conclusion that the lines are perhaps the 

 result of crystalline cleavages in saline 

 cakes deposited through desiccation. Pi- 

 nate impressions suggesting frost flower 

 pictures occur with the right line markings 

 and these were reproduced experimentally. 

 Slabs of the stone 2i square yards in size 

 and completely covered with the right lines 

 were taken from the deposit. 



Conglomerate ' puddings ' from the Paria River, 

 Utah. By J. E. Talmage, Salt Lake 

 City, Utah. 



The paper was an explanation of photo- 

 graphs, showing a number of fresh conglom- 

 erate masses, consisting of pebbles and mud 

 formed by accretion through rolling. The 

 formation of these puddings was observed 

 on the mud flats of the Paria. The sticky 

 mud and river, worn pebbles readily cohere; 

 and by rolling the lumps, increase in size 



